Despite the importance of strategic materials used into the fabrication of lithium secondary batteries, only few industrial processes were developed commercially to recycle specifically spent lithium batteries, both primary and secondary. Actually, at present only three major companies have developed commercial recycling processes for the neutralization and/or recovery of valuable by-products from spent lithium batteries and one is always developing at the pilot scale. Today the leading lithium battery recycler in the U.S. is Toxco, Inc. which is based in Anaheim, Calif. Toxco processes lithium batteries at its recovery plant located at Trail, British Columbia, Canada. Toxco operates a cryogenic process that is described in U.S. Pat. Nos. 5,345,033 and 5,888,463 and which is capable of recycling about 500 tonnes per year of spent lithium batteries. A major part of these are high performance batteries used as back-up power sources by the US Army (e.g., torpedoes, missiles). Hence numerous chemicals are recycled together without selective sorting (e.g., Li/SO2, Li/SOCl2, Li-Ion, lithium thermal batteries, and lithium reserve batteries). Essentially, the TOXCO process involves reducing the reactivity by lowering the temperature using cryogenic liquids such as nitrogen or argon. The frozen batteries are then immersed under a large volume of aqueous caustic solution made of sodium hydroxide and sodium carbonate. In this bath, the still frozen battery cases are crushed. Active cell materials, such as lithium, react to release hydrogen and heat. Under these harsh conditions, hydrogen ignites burning all flammable organic solvents. At the end of the process, cobalt and lithium carbonate, and in a lesser extent, paper and plastics, carbon black, and metal scrap are also recovered as secondary by-products. Lithium carbonate is purified by electrodialysis and sold by a subsidiary of Toxco, LithChem International. However the TOXCO process is not specifically appropriate to the recycling of lithium metal solid and gel polymer electrolyte batteries because it focuses on alkaline solutions for dissolution and does not focus on the particular vanadium chemistry.
The second company is BDT Inc. formerly Battery Destruction Technology which is located in Clarence, N.Y. BDT specializes in the destruction of hazardous wastes, particularly spent lithium batteries. The current processing capacity is about 350 tonnes per year of both spent lithium batteries and lithium metallic scrap. The process involved which is described in U.S. Pat. No. 4,647,928 consists in crushing the spent batteries under an alkaline aqueous solution of sodium hydroxide with a swing type hammer mill. The resulting sludge is clarified by sieving through a coarse screen, solid wastes are removed by filtration and recovered for disposal and landfilling, while the alkaline filtrate is pH adjusted and redirected to the mill. Unfortunately, this process which only intended to neutralize hazardous materials does not allow easy separation and recovery of valuable by-products such as lithium and vanadium compounds.
The third company is Sony Electronics Inc. which, in close collaboration with Sumitomo Metal Mining Company, has developed a process specifically devoted to recovering cobalt oxide from its own spent Li-Ion batteries used in electronic devices, such as laptop computers, camcorders, digital cameras, and cellular phones. The process involves the calcination of spent cells and utilizes the cogeneration resulting from burning electrolytes. It is capable of recovering cobalt oxide with a sufficiently high quality to reuse the latter directly in the fabrication of new Li-Ion batteries, and the metallic scrap consists of secondary by-product, such as copper and stainless steel. This technology is well established and recycling of spent lithium-ion cells is today performed in Japan with a current processing capacity of 120–150 tonnes per year. Improvement to this process is currently performed in a pilot plant that is located in the US at Dothan, Ala., with a R&D current capacity of 150 kg per year. However, the Sony-Sumitomo process was specifically intended to recover only cobalt oxide from Lithium-Ion batteries and cannot be applied to the lithium metal solid and gel polymer technology. Finally, several recent processes for the recovery of both cathodic materials and lithium from cell materials used in Li-Ion secondary batteries were also developed but were not implemented industrially. Finally the four following novel processes designed by Canon (U.S. Pat. No. 5,882,811), Kabushiki Kaisha Toshiba (U.S. Pat. No. 6,120,927), Tokyo Shibaura Electric Co. (U.S. Pat. No. 6,261,712),. and Merck Patent GmbH (EP 1056146), are all related to reclamation and recycling of lithium ion batteries. In conclusion, none of the above processes are devoted specifically to the treatment of lithium metal gel and solid polymer electrolyte batteries for recovering both lithium and vanadium therefrom.
Lithium metal polymer batteries, designated under the common acronym LMPB, are promising rechargeable power sources especially developed by the Applicant for automotive applications, such as hybrid electric vehicles (HEV), and fully electric vehicle (EV), and the stationary market, such as electric power utilities, telecommunications, etc. The basic electrochemical system of these secondary batteries is made of an anode consisting of an ultra-thin lithium metal foil, a solid copolymer electrolyte containing a lithium salt, a cathode comprising insertion lithium vanadium oxide compounds, and a carbon coated aluminium current collector. Owing to its thin film design, the electrochemical cell (EC) exhibits both high gravimetric (270 Wh/kg) and volumetric energy (415 Wh/kg) densities. An ultimate chemical analysis expressed in mass fraction of a typical electrochemical cell is presented in the following Table 1.
TABLE 1Ultimate chemical composition of an ECChemical elementMass fractionCarbon28.383 wt %Oxygen25.562 wt %Vanadium16.612 wt %Aluminium11.049 wt %Lithium10.222 wt %Hydrogen 3.879 wt %Fluorine 2.540 wt %Sulphur 1.438 wt %Nitrogen 0.315 wt %
However, in view of to their content of strategic cell materials, high energy density, and elevated chemical reactivity, spent lithium metal polymer batteries represent hazardous wastes that could lead to major economical, safety, and environmental issues in the commercialization of large lithium polymer batteries. Therefore, a large commercialization plant must provide for the recycling of these spent batteries in order to neutralize and deactivate these hazardous wastes particularly lithium metal, and lithium vanadium oxide due to their chemical reactivity, toxicity and corrosiveness, thereby ensuring a maximum plant health and safety; it must also recycle all the strategic cell materials in order to recover efficiently and in an economical manner the valuable by-products for decreasing production costs and preserving natural resources from acute depletion. Finally such plant should avoid any release of hazardous materials into the environment in order to fit in zero emission programs, developed by federal and government environmental agencies worldwide.